Devices for anchoring and extracting plugs in



1 WM??? SR gEAHCH 300M March 17, 1964 R. ROCHE ETAL 3,125,123

DEVICES FOR ANCHORING AND EXTRACTING PLUGS IN AND FROM FUEL CHANNEL OF NUCLEAR REACTORS Filed Aug. 10, 1962 2 Sheets-Sheet l FIGL'i March 17, 1964 ROCHE ETAL 3,125,123

DEVICES FOR AN RING AND EXTRACTING PLUG N AND FROM FUEL CHANNEL OF NUCLEAR REACT Filed Aug. 10, 1962 2 Sheets-Sheet 2 W. I n

IZI'i) A28 United States Patent DEVICES FOR ANCHORING AND EXTRACTING PLUGS IN AND FROM FUEL CHANNEL OF NUCLEAR REACTORS Roland Roche, Clamart, Jean-Marc Hiissig, Paris Orsay, and Pierre Cousseran, Clamart, France, assignors to Commissariat a IEnergie Atomique, Paris, France Filed Aug. 10, 1962, Ser. No. 216,231 6 Claims. (Cl. 138--89) This invention relates to a device for anchoring and extracting plugs in and from fuel channels of nuclear reactors which are adapted to receive nuclear fuel elements and through which a cooling fluid under pressure is circulated.

It is the object of this invention to provide anchoring and extracting devices of the type broadly set forth hereinabove which are designed with a view to meet various safety requirements while being capable of effecting a great number of channel opening and closing movements without failure.

More particularly, the device for anchoring and extracting plugs in and from fuel channels of nuclear reactors, which constitutes the subject-matter of this invention, is characterized notably in that it comprises, on a recessed portion of the plug, a plurality of pawls pivoted on said plug and adapted to lock same relative to the fuel channel to be closed, a member for locking said pawls which is axially movable inside said plug between two positions in which said pawls are locked and released relative to said channel, an inner shoulder adjacent to the open end of the plug and, on a clamp axially movable in relation to said plug, a plurality of levers axially fast on said clamp but pivoted thereon so as to be radially movable in relation thereto, each lever carrying on its end an outer projection and an inner projection, means for controlling the radial movements of said levers which are associated with means for controlling the axial movements of said clamp and lever assembly in relation to said plug between a first position in which said outer projections of said levers abut against the edge of said shoulder so as to stop said clamp at a predetermined distance from said plug, a second position in which said inner projections of said lever engage said locking member and said levers are retracted to permit their introduction into said plug, and a third position in which said clamp contacts said plug, said outer projections of said levers drivingly engage the shoulder and release the pawls and said inner projections keep said locking member in the unlocking position.

In addition to this main arrangement the invention also comprises other arrangements utilized preferably simultaneously as will be explained presently.

This invention contemplates more particularly a certain form of application and also certain forms of embodiment of the arrangements broadly set forth hereinabove; still more specifically, this invention is concerned, by way of novel industrial products, with devices of the type set forth which constitute a practical embodiment of the same arrangements, as well as the component elements and the special tools and means necessary for their construction, and finally any nuclear reactor equipped with devices of this character.

With the foregoing and other objects in view, the invention resided in the novel arrangements and combination of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention. Other objects and advantages will become apparent from the Patented Mar. 17, 1964 following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a fragmentary axial section showing a fuel channel plug and a handling clamp provided with an anchoring and extracting device constructed according to the invention and shown in the approach position of the clamp;

FIGURES 2, 3 and 4 illustrate in half axial section certain component elements of the structure shown in FIG. 1, respectively in the three positions following the preliminary position of FIG. 1; and

FIGURES 5 and 6 are half cross-sections taken upon the lines VV and VIVI of F IGS. 5 and 6, respectively.

Referring first to FIG. 1 of the drawings, the reference numeral 2 denotes the end portion of a channel, duct or receptacle normally closed by a plug 11 and formed with an annular projecting portion 13 of cylindrical configuration.

To simplify the disclosure, the terms outer and inner are used herein with the meaning remote from the channel axis and close to the channel axis respectively, and the terms front and back denote elements or portions located respectively close to and remote from an observer placed externally of the reactor and looking thereat.

According to this invention, the front corresponds to the top and the back to the bottom of FIGS. 1 to 4 of the drawings.

The device for anchoring and extracting a plug in and from a fuel channel of this character comprises, according to this invention:

A series of pawls 120 carried by the plug 11 and adapted to engage a groove formed in the wall of the end portion 2 of the channel for anchoring the plug therein;

A locking member 121 adapted to slide axially in a central passage formed in said plug for moving and subsequently holding the pawls in their anchoring position (FIG. 1); and

A handling clamp 122 movable in the axial direction relative to the channel and adapted to actuate the aforesaid locking member 121 and to move the plug 11 in the axial direction.

Under these conditions and according to a specific feature of this invention, a set of levers 123 are pivotally mounted on the clamp 122, each lever carrying on its back end an outer projection 124 and an inner projection 125, and being so pivoted that these back ends may move from an outer limit position (FIG. 1) to an inner limit position (FIGS. 2, 3 and 5). Furthermore, the front portion of plug 11 is formed with a central recess 133 in which a locking member 121 is axially movable, said recess being formed with an inner annular shoulder 126 adjacent to its open end. The locking member 121 is formed with a peripheral groove 127 in the vicinity of this shoulder 126.

It is advantageous to use locking pawls 120, which are preferably three or more in number, disposed at spaced intervals around the plug 11 in longitudinal slots 134 formed therein, these pawls being pivoted on the plug by means of transverse pins 128; each pawl 120 is formed on its back end with an outer heel 120a adapted to engage the groove 85 and on its front end with an inner face 12% of arcuate configuration (see FIGS. 5 and 6), the back end of the pawl being formed on the other hand with a bearing face 1200. The aforesaid locking member 121 consists of a substantially cylindrical rod formed with a widened-out portion 121a adapted to engage the inner bearing faces 1200 of the pawls for actuating same. On the other hand a compression coil spring 129 constantly urges the locking member 121 to its uppermost or front position in which it locks the pawls 120, this spring being mounted between the member 121 and the bottom of the central recess 133.

The levers 123 are disposed radially at spaced intervals around the clamp 122 and pivoted thereon by means of transverse pins 130, their simultaneous pivoting movement being positively controlled in either direction by means of an axial rod 131 adapted to slide axially in the clamp by engaging the inner edge of the levers with collar portions 131a having preferably rounded edges. The projections 124 and 125 have an arcuate contour visible in FIGS. and 6, the outer projection 124 being bound by an arcuate outer face 124a. Moreover, each lever 123 is formed, internally of the aforesaid face 124a, with a bearing face 132 also of arcuate configuration which is adapted to co-operate with the faces 12% of pawls 120.

As shown in FIG. 5 the outer faces 124a of the outer projections 124 are so shaped that in the innermost position of levers 123 they all lie on a same surface of revolution about the general axis (this surface of revolution being shown diagrammatically by the circle C), thus facilitating their movement along the inner cylindrical surface 126a of shoulder 126. In addition, as shown in FIG. 6, the bearing faces 132 are so designed that in the position wherein the levers 123 grip the plug 11 by engaging its groove 127 they all lie on a common surface of revolution about the main axis (this surface being shown diagrammatically by the circle C thus facilitating their engagement with the inner faces 12% of the pawls. Of course, the contours of the peripheral development of the inner faces 1201) of pawls 120 and faces 132 of levers 123 are such that in the plugretaining position of these levers (FIG. 6) the pawls cannot move through the gap then existing between the faces 132 of these levers. In FIG. 6 there is shown the most inadequate position in this respect, wherein the pawls are just level with these gaps in the peripheral direction, the most favourable position being of course the one in which each pawl is coincident or co-planar with the radial plane of a lever.

The clamp 122 may be part of a loading and unloading machine or device of any suitable type comprising preferably an intermediate clamp guiding sleeve 47, connected in a fluid-tight manner to the casing or like enclosure of the machine or device through means permitting axial or radial movements of its lower end 47a formed preferably with a tapered or part-spherical mouth 49 adapted to engage in a fluid-tight manner a gasket or like sealing member 50 carried by the aforesaid annular projecting portion 13, together with means controlling the sliding movement, in said intermediate sleeve 47, of the clamp and lever assembly. However, these control means as well as the means controlling the axial movements of rod 131 (which are associated with said clamp control means) are not shown in the drawings.

The fluid-tightness of the plug 11 is obtained by forming thereon preferably a first shoulder 98 adapted to engage a stop-forming face 99a coincident with a change in diameter between two sections of the channel to be plugged, namely sections 99 and 100. Moreover, this plug 11 formed below the shoulder 98 with another, somewhat tapered shoulder 101 coincident with another change in diameter 102 in the channel between sections 100 and 2, but the tapered shoulder 102 is so located along the channel bore that it cannot abut against the shoulder 101 of the plug. Gaskets 103 are also disposed on the plug between the cylindrical portion extending between shoulders 98 and 101;

This plug anchoring and extracting device operates as follows:

- When the plug 11 is positioned in the fuel channel 2 the shoulder 98 of its solid portion engages the end face 99a, the joint being sealed by the gaskets 103, the annular cavity 133 being relatively close to the upper 4 end of the channel. The plug is anchored by the heels 120a of pawls 120 engaging the annular groove 85. These pawls are locked in this position by the engagement of their faces 120a with the widened-out portion 121a of rod 121 kept in the desired position by the coil spring 129.

When it is desired to extract the plug 11, the sleeve 47 is lowered until its end 47a engages the projecting annular portion 13 of the channel, whereafter, the control means associated with rod 131 being so adjusted that the levers 123 are spread outwardly as shown in FIG. 1, the members controlling the movements of clamp 122 in sleeve 47 are operated, until the outer projections 124 engage the shoulder 126. Then the control rod is retracted in the direction of the arrow F (FIG. 1) up to the axial position shown in FIG. 2, whereby the complete set of levers are rocked in the clockwise direction, as seen in FIGS. 1-4, about their pivot pins 130, so that their lower ends lie inside the circle corresponding to the surface 126a of shoulder 126. Then the inner projections 125 engage the groove 127 of locking rod 121 and bear against this rod, so that the clamp can be moved in the direction of the arrow F until the outer projections 124 clear the shoulder 126, as shown in FIG. 3, this movement being facilitated by the shape of faces 124a as already explained hereinabove with reference to FIG. 5. During this movement the inner projections 125 push the locking member 121 inwards against the resistance of spring 129 until the widened-out portion 121a leaves the faces 1200 of pawls 120. Under these conditions these pawls 120 are released but remain nevertheless engaged in groove 85. Then rod 131 is moved upwards in the direction of the arrow F to the position shown in FIG. 4, thus causing the levers 123 to spread outwards, with the twofold consequence that the heels 120a of pawls 120 are extracted from groove due to the engagement of the lever faces 132 with the upper faces 12012 of pawls 120, and that the projections 124 are lowered beyond the shouder 126. Due to the specific shape of these faces 132, as already explained hereinabove with reference to FIG. 6, all the pawls are safely held in the same radial position upon completion of said spreading movement, irrespective of the axial tolerances existing between the clamp and the plug. Finally, from the position illustrated in FIG. 4 the plug can be removed by pulling the clamp 122 in the direction of the arrow F The plug can be refitted by repeating the same movements but in the reverse sequential order. When the inner projections engage the bottom of groove 127 to free the opposite or outer projections 124 from shoulder 126, the upper projections 12% of pawls 120 are released, thus tilting the heels 120a of these pawls and causing them to engage the outer groove 85 of the channel, and the upward movement of clamp 122 is attended by the same movement of levers 123 so that these levers will clear the inner surface 126a and carry along the locking member 121 until the widened-out portion 121a engages the inner faces 120c of the pawls. In this position, the levers 123 may be spread out again and the clamp lifted back into the loading machine. However, the clamp cannot be disengaged from the plug unless the latter is anchored in its channel by means of its pawls 120. In fact, if the heels 12011 are not engaged in the groove 85 the widened-out portion 121a cannot contact the inner faces 1200 and the central groove 127 cannot move to its foremost position as shown in FIG. 1, which is the only position permitting the outward movement of the levers with a view to remove the inner projections 125 from this groove 127 and to position the outer projections 125 above the shoulder 126 in order to release the clamp.

Although the present invention has been described in conjunction with a preferred embodiment, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

What We claim is:

1. A device for anchoring and extracting plugs in and from fuel channel of nuclear reactors, which comprises, on a recessed portion of the plug, a plurality of pawls pivoted on said plug and adapted to lock same relative to the fuel channel to be closed, a member for locking said pawls which is axially movable inside said plug between two positions in which said pawls are locked and released relative to said channel, an inner shoulder adjacent to the open end of the plug and, on a clamp axially movable in relation to said plug, a plurality of levers axially fast on said clamp but pivoted thereon so as to be radially movable in relation thereto, each lever carrying on its end an outer projection and an inner projection, means for controlling the radial movements of said levers which are associated with means for controlling the axial movements of said clamp and lever assembly in relation to said plug between a first position in which said outer projections of said levers abut against the edge of said shoulder so as to stop said clamp at a predetermined distance from said plug, a second position in which said inner projections of said lever engage said locking member and said levers are retracted to permit their introduction into said plug, and a third position in which said clamp contacts said plug, said outer projections of said levers drivingly engage the shoulder and release the pawls 6 and said inner projections keep said locking member in the unlocking position.

2. A device according to claim 1, in which said locking pawls are pivoted in longitudinal recesses formed at spaced intervals around said plug.

3. A device according to claim 2, in which all the outer faces of said levers, in the aforesaid retracted position, lie on a common surface of revolution about the channel axis, the diameter of said surface of revolution being smaller than that of said shoulder, and the outer surfaces of said inner projections are in the proper position for anchoring said levers on said shoulder along another surface of revolution co-operating with corresponding contours of the pawl end portions.

4. A device according to claim 1, in which said locking member consists of a rod formed with a cam portion adapted to engage said pawls and with a peripheral groove acting as an abutment relative to the inner projections of said levers in their retracted position.

5. A device according to claim 4, in which said levers have shaped portion and that said. control member comprises two widened-out portions adapted to engage said shaped portions of said levers, and disposed on either side of the pivot pins of said levers.

6. A device according to claim 5, in which the surface of the pawl ends is greater than the maximum distance between the ends of said levers in their plug-anchoring position.

No references cited. 

1. A DEVICE FOR ANCHORING AND EXTRACTING PLUGS IN AND FROM FUEL CHANNEL OF NUCLEAR REACTORS, WHICH COMPRISES, ON A RECESSED PORTION OF THE PLUG, A PLURALITY OF PAWLS PIVOTED ON SAID PLUG AND ADAPTED TO LOCK SAME RELATIVE TO THE FUEL CHANNEL TO BE CLOSED, A MEMBER FOR LOCKING SAID PAWLS WHICH IS AXIALLY MOVABLE INSIDE SAID PLUG BETWEEN TWO POSITIONS IN WHICH SAID PAWLS ARE LOCKED AND RELEASED RELATIVE TO SAID CHANNEL, AN INNER SHOULDER ADJACENT TO THE OPEN END OF THE PLUG AND, ON A CLAMP AXIALLY MOVABLE IN RELATION TO SAID PLUG, A PLURALITY OF LEVERS AXIALLY FAST ON SAID CLAMP BUT PIVOTED THEREON SO AS TO BE RADIALLY MOVABLE IN RELATION THERETO, EACH LEVER CARRYING ON ITS END AN OUTER PROJECTION AND AN INNER PROJECTION, MEANS FOR CONTROLLING THE RADIAL MOVEMENTS OF SAID LEVERS WHICH ARE ASSOCIATED WITH MEANS FOR CONTROLLING THE AXIAL MOVEMENTS OF SAID CLAMP AND LEVER ASSEMBLY IN RELATION TO SAID PLUG BETWEEN A FIRST POSITION IN WHICH SAID OUTER PROJECTIONS OF SAID LEVERS ABUT AGAINST THE EDGE OF SAID SHOULDER SO AS TO STOP SAID CLAMP AT A PREDETERMINED DISTANCE FROM SAID PLUG, A SECOND POSITION IN WHICH SAID INNER PROJECTIONS OF SAID LEVER ENGAGE SAID LOCKING MEMBER AND SAID LEVERS ARE RETRACTED TO PERMIT THEIR INTRODUCTION INTO SAID PLUG, AND A THIRD POSITION IN WHICH SAID CLAMP CONTACTS SAID PLUG, SAID OUTER PROJECTIONS OF SAID LEVERS DRIVINGLY ENGAGE THE SHOULDER AND RELEASE THE PAWLS AND SAID INNER PROJECTIONS KEEP SAID LOCKING MEMBER IN THE UNLOCKING POSITION. 